After successfully lighting the water heater, allow the
unit to operate for 15 minutes and check the drafthood
relief opening for proper draft. Pass a match flame
around the relief opening of
the drafthood. A steady
flame drawn into the
opening indicates proper
draft. If the flame flutters or
is blown out, combustion
products are escaping from
the relief opening. If this
occurs, do not operate the
water heater until proper
adjustments or repairs are made to the vent pipe
system.
Burner Flames
Stacking
Emergency Shut Down
Inspect the burner
flames through the
viewport and compare
them to the drawings in
Figure 18. A properly
operating burner
should produce a soft
blue flame. Blue tips
with yellow inner cones
are satisfactory. The tips of the flame may have a slight
yellow tint. The flame should not be all yellow or have a
sharp blue-orange color. Contaminated air may cause
an orange colored flame. Contact a qualified service
technician if the flame is not satisfactory.
Stacking occurs when a series of short draws of hot
water (3 gallons or less) are taken from the water
heater tank. This causes increased cycling of the
burner and can result in increased water temperatures
at the hot water outlet. An anti-scald device is
recommended in the hot water supply line to reduce the
risk of scald injury.
Important:
Should overheating occur or the gas supply
fails to shut off, turn off the water heater’s manual gas
control valve and call a qualified service technician.
Water Temperature Regulation
UNITROL
BEFORE
LIGHTING
READ
ALL
INSTRUCTIONS
CAU
TIO
N
H
O
T
W
A
R
M
V
A
C
A
T
IO
N
CA
UTION
W
A
TE
R INCREA
SE
S
HOTTER
T
H
E
RIS
K OF SCALD
IN
JU
R
Y
V
A
C
A
TIO
N
W
AR
M
H
O
T
120°F
Bar
130°F
Bar
Index
Bars
Gas
Control
Knob
Figure 19
Robertshaw Gas Valve/Thermostat
Settings
W
ARNING
Dial
Stop
130°F
Bar
Reset
Button
Note:
During low demand periods when hot water is
not being used, a lower thermostat setting will reduce
energy losses and may satisfy your normal hot water
needs. If hot water use is expected to be more than
normal, a higher thermostat setting may be required to
meet the increased demand. When leaving your home
for extended periods (vacations, etc.) turn the
temperature dial to its lowest setting. This will maintain
the water at low temperatures with minimum energy
losses and prevent the tank from freezing during cold
weather.
Burn Hazard
Do not touch vent.
Doing so can result in
burns.
Checking the Draft
The thermostat is adjusted to its lowest temperature
when it is shipped from the factory. Water temperature
can be regulated by moving the temperature dial to the
preferred setting.
The preferred starting point is
120°F.
Align the index bar on the thermostat with the
desired water temperature as shown in Figure 19.
There is a hot water scald potential if the
thermostat is set too high.
Important:
Adjusting the thermostat past the 120°F bar
on the temperature dial will increase the risk of scald
injury. Hot water can produce first degree burns within:
120°F (49°C) more than 5 minutes
130°F (54°C) at 20 seconds
140°F (60°C) at 3 seconds
150°F (66°C) at 1-1/2 seconds
160°F (71°C) at less than 1 second
Figure 17
Match
Relief
Opening
Figure 18
Flame Characteristics
Tips may have
a yellow tint
Yellow inner
cones are
satisfactory
Correct flame
soft blue
Incorrect flame
lazy yellow
Water temperature over 125°F can cause
severe burns instantly or death from
scalds.
Children, disabled and elderly are at
highest risk of being scalded.
Feel water before bathing or showering.
Temperature limiting valves are
recommended.
18
